Swap Fees Explained: What Holding a Trade Overnight Really Costs
Each faint trail is one simulated future for this strategy. The bold line is the median — half of runs finished above it, half below. The shaded band spans the lucky 10th to unlucky 90th percentile, so an outcome inside the band was reasonable to expect; outside, less so.
- Swap is an interest charge (or credit) applied to positions held past the daily rollover
- It is charged per lot, per night — so it grows with both position size and holding time
- Most brokers charge three days of swap on Wednesday night to cover the weekend
- On a multi-week swing trade, swap can take a meaningful share of your target
- Check your broker's swap table for your pair and direction before entering
Day traders rarely think about swap. Swing traders should think about it every time they plan a trade. Swap is the overnight financing cost (or credit) on a leveraged position. It is small per night and easy to ignore — until a trade sits open for two or three weeks.
Where swap comes from
A forex position is effectively borrowing one currency to hold another. Each currency has an interest rate. If you are long the higher-yielding currency, you may earn a small credit. If you are long the lower-yielding one, you pay. Brokers then add their own markup, which is why many retail swaps are negative in both directions.
How to calculate it
Brokers publish swap as either points per lot or a currency amount per lot per night. The simplest form:
Total swap = Swap per lot per night × Lots × Nights heldRemember the triple-swap night. Because spot forex settles two business days forward, holding past rollover on Wednesday covers Saturday and Sunday as well. Most brokers apply three nights of swap that day. Some instruments, such as certain indices and commodities, use Friday instead — check your broker.
A worked example
Illustrative figures — real swap rates change with central bank rates and differ by broker.
| Value | |
|---|---|
| Position | 2 lots, long |
| Swap rate | −$7.00 per lot per night |
| Holding period | 14 calendar days (10 trading nights incl. two triple nights) |
| Nights charged | 14 |
| Total swap | 2 × $7.00 × 14 = −$196 |
| Trade target | $400 |
| Share of target lost to swap | 49% |
In this example, half of the planned profit goes to the broker before price has to move at all. That is the cost the Overnight Swap Drag tool is built to surface.
How swap changes your expectancy
Swap behaves like a cost that scales with time rather than with the number of trades. A strategy that holds positions for days has to earn its edge net of swap. If your average winner is held 10 nights and your average loser is held 3, swap reduces your winners more than your losers — the opposite of what you want.
Three practical steps:
- Add expected swap to your cost per trade when calculating expectancy
- Compare swap direction before choosing a pair — the same idea can be cheaper to express on a different cross
- For long holds, check whether your broker offers swap-free accounts and what fee replaces the swap